Manufacture of hydrocarbons



Patented Nov. 17, 1936 UNITED STATES 7 2,060,871 MANUFACTURE ornrnaocnanons Vladimir Ipatiefl, Chicago, Ill., as signor to UniversalOil Products Company, Chicago, 111., a corporation of Delaware NoDrawing. Application June 22, 1933,

Serial No. 677,079

8 Claims. (Cl. 196-10) This invention relates more particularly to thetreatment of olefinic hydrocarbons which are normally gaseous atordinary temperatures and pressures.

Olefinic hydrocarbons with which the present invention is concernedoccur along with corresponding paraflinic or saturated hydrocarbons incommercial hydrocarbon mixtures such as those encountered in thecracking of petroleum, in gas making processes and as by-products invarious chemical industries. In general they are more chemically activethan other classes of hydrocarbons, particularly it they contain morethan one double bond or triple bonds between carbon atoms. Even whenunder mild catalytic influence they exhibit this reactivity in theirpronounced tendency to polymerize and form substances of highermolecular weight. In some instances this instability may be -adisadvantage, particularly in the case of cracked hydrocarbon oildistillates which are of suitable boiling range to permit their use ininternal combustion engines, since the polymers which develop on storageare or a gummy character and impart color to the oil.

The present process provides for more eil'ectively utilizing theoleflnic constituents of commercial hydrocarbon mixtures particularlythose occurring in the gases from oil cracking processes to producevaluable derivatives therefrom and it may also be applied to individualoleflns produced by special chemical methods or by fractionation ofmixtures.

In one specific embodiment the invention comprises the treatment ofnormally gaseous oleflnic hydrocarbons with phosphoric acid' containingmetal salts as promoter catalysts to controllably produce polymerstherefrom which are utilizable as constituents of motor fuel. Salts ofzinc are preferred.

To assist in developing the exact character of the invention thefollowing table is introduced, which gives the formulas and boilingpoints of some of the lower molecular weight oleflns:

Compounds Formula ai ga 852813 2551 2: op one Ethy ethylene CH;CH;OH=CH:-5 dimethylethylene CH;.CH=CH.CH= Unsym. dimethylethylene (0H,)1C=CH| 6n-Propyl ethylene nmunylene CH;CH:CH;CH=CH1- +39 Isopropylethylenea-isoamylene (CH;)1CH.CH=CH2--- +21 Bo Compounds roman Ef Sym. methylethyl ethylene fi-amylene CHa.OH|.CH-=CH.CH| +86 Unsynninethylethylethylene CH CH 'y-flllly ene S- r 31 V o=orn.... Tral gethyllethylene CH) c oamy one =CH.CH Tetramethyl ethylene CHfliC =C(CH:):

The boiling points given in the table indicate that the tour carbon atommembers are gaseous at ordinary temperatures and that the flve carbonatom members may readily exist in minor' proportions in commercial gasmixtures, such as the cracked hydrocarbon mixtures with which thepresent invention in specially concerned.

The present process is particularly directed to the production of dimersand trimers i'rom monooleflns, particularly such oleiins whose dimersand trimers boil between the approximate range of commercial motor fuel,say, for example, from 100 to 400 F. It has been found that the dimersand some of the trimers of propylene, the butylcues and amylenes boilwithin this range and furthermore, that these compounds have unusuallyhigh anti-knock characteristics. The following table shows theapproximate boiling points of the dimers of propylene, butylenes,amylenes and hexylenes which all occur in appreciable quantities in thegases from oil cracking processes:

Boiling points of olefin dimers "F. Hexylene 155 Octylene 255 Decylene323 Dodecylene 417 Ethylene is as a rule the most resistant to theaction of the preferred catalyst mixtures but by a suitable choice ofpromoter catalysts and conditions of operation it may be caused topolymerdesired direction without the formation of the higher molecularweight substances mentioned. Concentrated phosphoric acid of commercialgrade may be employed and in some instances. particularly wheretheconcentration of oleflns is .low in the gas mixture, the temperaturemay be raised considerably, sometimes as high as 200 C. so that thedesired reactions are accelerated and yet there is no undue formation ofundesirably heavy polymers. Any desired pressure may be employed, theinfluence of this factor being principally to increase the capacity of;apparatus though pressure may also accelerate the reactions ofpolymerization. When low or moderate temperatures are employedliquefaction of some olefins will occur if the pressure employed isabove the critical pressure, this further assisting in increasingcapacity of equipment and intimacy of contact.

The compounds which may be employed as promoter catalysts in phosphoricacid comprise various salts of metals such as, for example, phosphates,chlorides or sulphates of aluminum, zinc, cadmium, mercury, iron,nickel, cobalt, copper, magnesium, etc. The use of any particular metalsalt will be limited by its solubility in phosphoric acid of anyparticular strength. Concentrations of salts as high as 20% of thephosphoric acid may be used when the salts are suillciently solublethough as a rule amounts of from 2 to 10% are sufllcient foraccomplishing the desired acceleration of the catalytic eifect of theacid. The additional catalytic effect observed in these cases may be dueeither to the basic or the acid radicals, or both. It is obvious thatmetal oxides or metals themselves may be dissolved in phosphoric acid toan extent depending upon the solubility of the phosphates formed.

The salts which may be thus employed to accelerate and modify thecatalyzing eflect of phosphoric acid upon oleilns comprise a number ofclasses which differ from each other in many of their physical andchemical characteristics. 'Itis to be understood that the differentsalts which may be used are not exact equivalents in their action butthat each exerts its own peculiar influence upon the catalyzing power ofthe base ma-,

'terial, to-wit: the phosphoric acid. The field of catalysis is to alarge extent still in an experimental state even though many substanceshave been found by empirical methods to have special value in certainreactions. erally the best catalyst for hydrogenatlng fatty oils and theoxides of vanadium are generally the fist for catalyzing the productionof sulphur trl oxide from sulphur dioxide-oxygen mixtures. In thepresent instance diiferent salts may be chosen which will producedecidedly better results than others when working with olefln gasmixtures of varying composition. Particular instances. of metal saltswhich have positive accelerating action and others which have a neutralor a negative effect will be developed in subsequent examples.

Ordinary ortho-phosphoric acid, HsPO4, is generally the preferred acidof phosphorus for use in connection with reactions of the presentcharacter. However, it is within the scope of the invention to employother acids of phosphorus insofar as they possess suilicient catalyzingactivity either alone or after the addition of promoter catalysts.

Thus, nickel is gen- In producing low boiling polymers from gaseousoleflns or mixtures thereof such as are encountered in commercialhydrocarbon gases, the

simplest mode of operation consists in bubbling the gas mixture througha stationary body of acid catalyst mixture of regulated strength andcomposition containing a selected promoter catalyst, using cooling coilsor precooled gases to keep down the temperature rise if this is shown tobe necessary. Atmospheric temperatures and pressures are frequentlysumcient to produce good treating effects but,aspreviouslystated,temperatures as high as 200 C. may be employed andsuperatmospherlc pressures of the order of 10 to 20 atmospheres may beused with safety if the time of contact and the amount of catalyst areproperly chosen. When operating with more or less pure olefins or gasmixtures of high olefin content, a control is ofiered in blending themixture with some inert gas such as hydrogen or nitrogen to assist incontrolling the rate of reaction. Batch treatments may be conducted inautoclaves, or, if desired, continuous counterflow treatments may beemployed as these are known in the art, and in such cases the gasmixture may be passed upwardly counter-current to descending streams ofacid catalyst mixture in towers containing filling or packing materialor regularly spaced trays to assist in subdividing the stream of,catalyst. The polymerized oleflns will appear as a layer upon thesurface of the acid in the case of the first mentioned batch method oftreatment, from which they may be removed continuously orintermittently. When employing the counter-current tower operation,liquid will be recovered from above the acid after settling inintermediate accumulators.

A marked advantage in the use of phosphoric acid catalysts containingmetal salt promoters resides in the fact that very little solution oforiginal oleflns or their polymers occurs therein. The consumption ofacid is small and a given amount may be used repeatedly without thenecessity for purification steps which must ordinarily be employed inremoving sludge products from such powerful polymerizing and condensingagents as sulphuric acid, aluminum chloride, etcetera. Neitherphosphoric nor phosphorous acid has any pronounced oxidizing actionunder suitable conditions of treatment so that condensation reactionsdue to removal of hydrogen or abstraction of water are substantiallyabsent.

The present type of catalyst comprising phosphoric acid as a base andcontaining minor amounts of metal salts as promoters possess theadvantage of maintaining their activity over long periods of time andproducing high yields of relatively low'boiling liquid hydrocarbonpolymers per unit weight of catalyst material. Use of the inventionindicates that there is some ester formation with the phosphoric acid,which reaction, however,

does not lower but frequently enhances the catalytic power of themixture. Extensive formation of esters after a certain concentration isreached may result in the formation of small yields of 7 alcohols suchas, for example, isopropyl alcohol, but this production is seldom oi!serious consequence. Such alcohols as may be formed, it not desired as aconstituent oi the liquid hydrocarbon polymers, are removable bysolution in water.

In carrying out the invention the apparatus used and the conditions ofoperation chosen in respect to temperature, pressure, proportioning ofreacting constituents, choice of acid and promoter catalyst, etcetera,will be varied to suit individual cases. when the process is used topolymerize individual oleflns or mixtures of known composition, it ispossible to so regulate the treatments that compounds or mixtures ofcompounds of very definite composition may be produced. For example, anyone oithe olefins given in the first table (with the possible exceptionoiethylene) may be polymerized to form a corresponding polymer with amixture 2 TABLE I Polymerization of propylene with 89% phosphoric acidat atmospheric pressure Tom rature Per cent Catalyst 0. liquid yield I89% mro. 155-160 a. s 89% HsPOrl-5% Z11. 150-160 7. 7 89% HSPO+5%150-155 15. 2 89% H:P MgCiz 155-160 16. 0

This data shows that the presence of zinc phosphate (resulting from thesolution of zinc in phosphoric acid) doubled the liquid yield under agiven set of experimental conditions, while the same percentageincreased the yield tour times over that obtainable with the acid alone.

The following data shown in Table II shows the results of twocomparative experiments run at atmospheric pressure using 100%phosphoric acid with and without the addition of 5% anhydrous coppersulfate:

Table II Tom rature Percent liquid Catalyst yield 100% HsPO4 100%HsPO4-5% 01.1304

The effect of the promoter in this case was to double the yield ofliquid products, even when employing a higher rate of gas flow in theapparatus. Owing to the use of the anhydrous salt there may have beensome efiect due to the dehydration of the acid.

In Table 111 data is introduced to show that minimum production oiundesirable by-products from side reactions.

' slum borofluoride slowed up chloride in approximately the certainsalts may have a neutral or negative eflect;

Table III Part 1 Max. Final Percent Catalyst Temp. C. pres. pres. liquidkg./cm. kg./cm. y old 89% HaPO4 150 39 25 41. 8 89% HsPO|+Cds(P04):-.-150 40 25 43. 0 89% H3P0|+Cd(CiH!OI)L 150 41 31. 5 29. 0 89% HsPO|+CuCh150 43 37 21. 4 89% HaPOrl-KBF; 150 35 28 22. 2

Part 2 100% H.Po.+ouci. 125 as as o. o 100% H:PO4+CHSO4 125 38 24 32. 8

The data shows that cadmium phosphate (produced by dissolving metalliccadmium in the acid) had a very slight positive catalytic action whilecadmium acetate, cuprous chloride and potasthe catalytic activity of theacid, and therefore stance were not desirable. Such salts, however, inthe case 0! more readily polymerizable olefins, may have value inpreventing over-polymerization with concurrent production of highboiling polymers of a tarry character which are unsuitable asconstituents of motor fuel.

The comparative data shown in Part 2 of the table between cupricchloride and cupric sulfate indicate some of the variations to beexpected when using diiierent salts. The copper sulfate is again ofoutstanding value in accelerating the action under the conditions of theexperiment which it will be noted difier from the conditions in Part 1in the use oi a lower temperature;

- The character of the invention is sufliciently described in thepreceding specification and its value is brought out by the experimentaldata introduced, but neither is to be construed as im- .posing unduelimitations thereon except as hereinbefore specified.

I claim as my invention:

1. A process for converting normally gaseous olefins into hydrocarbonliquids which comprises polymerizing the olefins in the presence of acatalytic acid of phosphorus and a metallic salt which promotes thecatalytic activity of the acid and selectedfrom the group consisting ofthe phosphates, chlorides, and sulphates oi aluminum, zinc, cadmium,mercury, iron, nickel, cobalt, copper, and magnesium.

2. A process for converting normally gaseous olefins into hydrocarbonliquids which comprises polymerizing the olefins in the presence of aphosphoric acid and a metallic salt which promotes the catalyticactivity of the acid and selected from the group consisting of thephosphates, chlorides, and sulphates of aluminum, zinc, cadmium,mercury,'lron, per, and magnesium.

3. A process for converting normally gaseous oleflns into hydrocarbonliquids which comprises polymerizing the oleflns in the presence ofpyrophosphoric acid and a metallic salt which promotes the catalyticactivity or the acid and selected from the group consisting of thephosphates, chlorides, and sulphates of aluminum,

nickel, cobalt, copin the present ina zinc, cadmium, mercury, iron,nickel, cobalt, copper, llld 11118116811118.

converting, normally saseous liquids which com- 4. A process for olennsinto pxisespolynierizingtheoiennsinthepresence' 01' a phosphoric acidsolution having dissolved therein a metallic salt which promotes thecatalytic activity of the acid and selected from the group consisting ofthe phosphates, chlorides, and sulphates of aluminum, zinc, cadmium,mercury. iron. nickel, cobalt, copper, and magnesium. 5. A process forconverting normally-gaseous olenns into hydrocarbon liquids whichcomprises polymerizing the olenns in the presence oi. a phosphoric acidand a'zinc salt.

oleflns into hydrocarbo liquids which comprises the oleflns in thepresence 01' pyrophosphoric acid and a zinc salt.

7. A process for converting normally olenns into hydrocarbon liquidswhich comprises polymerizing the olcnns in the presence of a phosphoricacid solution having a zinc salt dissolved therein.

8. A process for converting normally gaseous oleflns into hydrocarbonliquids which comprises polymerizing the oleflns in the presence or acatalytic acid of phosphorus and a zinc salt.

VLADDIIR IPA'I'IEFF. 1

